Friday, May 26, 2017

Vitamin D in pregnancy may help prevent childhood asthma

A new study published today in the Journal
of Allergy and Clinical Immunology has found that taking Vitamin D
supplements in pregnancy can positively modify the immune system of the newborn
baby, which could help to protect against asthma and respiratory infections, a
known risk factor for developing asthma in childhood.

The team of researchers from King's
College London looked at the effect that taking a supplement of 4,400 IU
vitamin D3 per day during the second and third trimesters of pregnancy versus
the recommended daily intake (RDI) of 400 IU/day, had on the immune system of
the newborn.

Participants were randomised at 10 -
18 weeks of pregnancy to high or low doses of vitamin D supplements. The team
then took umbilical cord bloods from 51 pregnant women to test the
responsiveness of the newborn's innate immune system, which form the body's
first line of defence to infection, and T lymphocyte responses, which provide
longer-lasting protection.

They found that blood samples from
babies born to mothers supplemented with higher vitamin D3 responded to mimics
of pathogen stimulation by greater innate cytokine responses and greater IL-17A
production in response to T lymphocyte stimulation. Both types of response are
predicted to improve neonatal defence to infection. Given the evidence for
strong immune responses in early life being associated with decreased
development of asthma, the team believe the effect will likely lead to improved
respiratory health in childhood.

"The majority of all asthma
cases are diagnosed in early childhood implying that the origin of the disease
stems in foetal and early life," said lead researcher, Professor Catherine
Hawrylowicz from King's College London.

"Studies to date that have
investigated links between vitamin D and immunity in the baby have been
observational. For the first time, we have shown that higher Vitamin D levels
in pregnancy can effectively alter the immune response of the newborn baby,
which could help to protect the child from developing asthma. Future studies
should look at the long-term impact on the immunity of the infant."

Dr Samantha Walker, Director of
Research and Policy at Asthma UK, said "Vitamin D is a promising area of
research for asthma, however this study is just the first step of many needed
to explore this topic. Although this study shows that vitamin D supplementation
in pregnancy may improve immune responses, much more research is needed to
prove whether this does in fact lead to reduced asthma rates later in life.